Valve for rock drills



June 22, 1937. w. A. SMITH, SR 2,084,554

VALVE FOR ROCK DRI'LLS Filed April 2, 1936 4'1 HI 5 ATTORNEY.

Patented June 22, 1937 UNITED STATES PATENT OFFICE VALVE FOR ROCK DRILLS William A. Smith, Sr., Athens, Pa., assignor to Ingersoll-Rand Company, Jersey City, N. J., a corporation of New Jersey Application April 2, 1936, Serial No. 72,318

2 Claims. (Cl. 1221-28) This invention relates to rock drills, and more and rear ends of the valve chamber through pasparticularly to a distributing Valve for fluid actusages 39 and 40, respectively. The pressure fluid ated rock drills, may be introduced directly into the supply pas- One object of the invention is to assure rapid sage 38 from a throttle valve 4| housed by a back 5 and positive action of the valve, and another obhead 42 forming the rearmost casing part of the o ject is to assure a heavy and forceful blow of the rock drill.

percussive element against the working imple- Intermediate the ends of the valve is an extermehtnal flange 43 of which the front and rear surfaces Ot er Objects will be in part obvious and in constitute actuating surfaces 44 and 45, respecpart pointed out hereinafter. tively. The surfaces 44 and 45 are subjected in- 10 In the drawing accompanying this specification termittently to pressure fluid for actuating the and in which similar reference numerals refer valve. That acting against the surface 44 for to similar parts, that purpose is conveyed thereto by a kicker pas- Figures 1 and 2 are longitudinal views, in seca e 46 pening int the piston chamber 22 at a tion, of a rock drill constructed in accordance p t w rdly of t e ex a t DO t d a 5 with the practice of the invention and showing k r passage 41 leads f m the piston Chamthe valve in its limiting positions. ber 22, at a point rearwardly of the exhaust port Referring more particularly to the drawing, 24 to convey pr fl d t0 the actuating designates the rock drill comprising a cylinder 2| face 45.

20 which is bored to form a piston chamber 22 con- To the end that the value of the pressure fluid taining a reciprocatory hammer piston 23. V The supplied to t e actua g surfaces 44 and 45 may piston chamber has a free exhaust port 24 which be immediately reduced after shifting the valve is controlled by the piston 23. the front and rear ends of the portion of the The piston shown is of the differential type, valve chamber containing the flange 43 are pro- 25 having a stem 25 on its front end which extends vided with vents 48 which open into an exhaust slidably through a washer'26 in the front end of pa sage 9, in t e Valve chest, leading t0 the the cylinder to deliver blows against a working atmosphere. implement (not shown). In the form of the invention illustrated the In the rear end of the cylinder 2| is an enlarged front and rear ends of the valve serve as holdbore 21 to accommodate a valve chest 28 coming surfaces 50 and 5| against which the presprising, in the present instance, a series of plates sure fluid flowing from the supply passage 38 to 29, 30 3| and 32 which are arranged in the order the inlet pas a t f r holdin th v lv in named from the outer end of the bore 21, the its limiting positions. The surfaces 50 and 5| plate 32 being the innermost of the group and also se ve as seati g portions of the ValVe- They forms a closure for the rear end of the piston Coopera With Seating Surfaces 52 and 53 011 the 35 chamber 22. plates 32 and 30 to limit the travel of the valve 1 The plates 30 and 3| are suitably bored to and to seal the ends of the valve chamber from form a valve chamber 33, and on the plate 29 is t e inlet passagesan extension 34 that extends through the plates To the end that the piston 25 may deliver a 33 and 3| and forms an inner bounding surface powerful blow against the working implement 40 for the valve chamber 33. The valve chamber and travel its full nominal stroke in both direcis thus of annular shape and contains a valve 35 tions unhampered by compression, the extenof the sleeve'type for distributing pressure fluid sion 34 is provided with front and rear relief to the ends of the piston chamber to actuate the passages 54 and 55 communicatin W t the inlet piston. Such pressure fluid is conveyed into the passa s 36 and 3 esp y, and Opening into 45 rear end of the piston chamber by an inlet pasthe periphery of the extension 34. The extension sage 35 in the p1ate32 and opening into the front 34 is further provided with a discharge passage end of the valve chamber, and an inlet passage 56 which opens into the periphery of the exten- 31 in the cylinder 2| and the valve chest 28 consion 34 at a point intermediate the passages 54 5 veys pressure fluid from the rear end of the valve and 55 and extends through the extension 34 5o chamber 33 to the front end of the piston and the plate 29 to the atmosphere. The paschamber. sages 54 and 55 are placed alternately in commu- The pressure fluid employed for this purpose is nication with the passage 56 by an internal anconveyed to the valve chamber 33 by a supply nular groove 51. in the valve 35. 55 passage 38 which communicates with the front In the form of the invention shown the exten- 55 sion 34 serves both as a guide member for the valve and for a rifle bar 58 Which extends rotatably therethrough and interlockingly engages the piston 23 in a well known manner. The rifle bar has the usual head 59 which carries springpressed plungers 69 adapted to engage the teeth iii of a ratchet ring 62 in the back head 42 for effecting a step-by-step rotary movement of the piston and the implement which it actuates, in to a manner well understood.

The operation of the device is as follows: With the valve 35 and the piston 23 in the rearmost limiting positions illustrated in Figure 1, pressure fluid flows through the passage 39 across the holding surface 59 of a valve, thereby holding the valve immovable, thence passes through the inlet passage 36 into the rear end of the piston chamher and actuates the piston on its working stroke;

When, during this stroke, the piston overruns the exhaust port 2 a portion of the air in the front end of the piston chamber is expelled through the inlet passage Lil, the relief passage 55, the groove 5'3 and the passage 55 to the atmosphere instead of being compressed. Air in advance of the piston will continue to flow from the front end of the cylinder until the valve is again shifted forwardly and only the air then remaining in the front end of the piston chamber will be compressed.

The shifting of the valve to the new position Will occurimmediately before the rear end of the piston chamber is opened to the atmosphere and follows the uncovering of the kicker passage Ell by the piston. When this kicker passage is uncovered pressure fluid flows to and acts against the actuating surface 45 and throws the valve 35 forwardly against the seating surface 52. Pressure fluid will then flow from the passage it! across the holding surface 5! thence through the inlet passage Bl into the front end of the piston chamber and, in passing over the holding surface 55, will hold the Valve firmly against the seating surface 52.

The pressure fluid admitted into the front end of the piston chamber drives the piston rearwardly, and after the piston covers the exhaust port 26 a portion of the air in the rear end of the piston chamber is expelled through the relief passage 5 2-, the groove El in the valve, thence through the passage 56 to the atmosphere.

As the piston proceeds rearwardly it uncovers the kicker passage a6. Pressure fluid then flows to the actuating. surface 44 and again throws the valve rearwardly to a position in which the holding surface 5! rests upon the seating surface 53 to seal the rear end of the valve chamber, thus completing the cycle of operations.

I claim:

1. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston therein, an exhaust port for the piston chamber, a valve chest having a valve chamber and a supply passage, front and rear inlet passages leading from the valve chamber to the pis ton chamber, a valve in the valve chamber to control communication between the supply passage and the inlet passages, opposed actuating surfaces on'the valve intermittently exposed to pressure fluid valved by the piston for throwing the valve, holding surfaces on the ends of the valve exposed to pressure fluid flowing to the inlet passages for holding the valve, seating surfaces in the valve chamber for the holding surfaces, a guide member within the valve, and passages in the guide member controlled by the valve for relieving compression from the piston chamher.

2. In a fluid actuated rock drill, the combination of a casing having a piston chamber and a piston therein, an exhaust port for the piston chamber, a valve chest having a valve chamber and a supply passage, front and rear inlet passages leading from the valve chamber to the piston chamber, a'valve in the valve chamber to control communication between the supply passage e and the inlet passages, opposed actuating surfaces on the valve intermittently exposed to pressure fluid valved by the piston for throwing the valve, holding surfaces on the valve exposed to pressure fluid flowing to the inlet passages for holding the valve, seating surfaces in the valve chamber for the holding surfaces, a guide member within the valve having an exhaust passage, relief passages in the guide member communicating with the inlet passages, and an internal groove in the valve toestablish communication between the relief passages and the'exhaust passage for relieving compression from the piston chamber.

WILLIAM A. SMITH, SR. 

